With the development of future soldier systems by many countries there has been a significant increase in the number of electronic devices that are being carried by soldiers. Some of these devices are stand alone and do not require communication to operate. Devices such as flashlight, laser aiming device or laser dazzler etc. need only be provided with battery power to function. Other devices including various video displays such as GPS, heads up displays, PDA type displays; or input devices such as a computer mouse or pointing device, keyboard; input-output devices such as microphone headsets, all require the use of cables to communicate with a central computer or between themselves. In some cases these devices may also draw power from the communications cable.
All of these devices require complex cable and wiring harnesses which are heavy, thick and stiff terminated with a variety of connectors, and that as a system create a myriad of human factor and mechanical issues when loads such as packs are placed over them. Individual wires are frequently subject to failure within the wiring harness as well as the documented high failure rate of connectors. In addition, the weapon sub system and helmet subsystem support many electronic devices which must communicate with and in some cases receive power from the torso. Cables which run between the weapon and helmet and the soldiers torso are typically called umbilicals or tethers. These cables can be very limiting, frequently catching or snagging on anything from doorknobs to vehicle attachments and corners as well as branches in the forest. When the cables snag they can either harm the soldier as his forward movement is suddenly stopped; restrain him so he cannot obtain cover from fire, or the cable is violently pulled from its socket frequently causing damage to either end of the connector or the cable itself even when the connector is of a quick release design.
As taught to us by recent events, soldiers in present and future wars and police and domestic agencies controlling riots or hostage type situations employ Radio Frequency (RF) jamming devices to prevent the activation and use of various radio devices. In domestic applications this may be the use of cellular phones that would be used for verbal communication or as a triggering device for an explosive. In military applications the RF jammer can be used to protect individual soldiers, but more typically is used to protect individual vehicles or convoys of vehicles in areas that have been laid with Improvised Explosive Devices (IED's) that are detonated remotely by radio frequency by a variety of simple transmitters.
It is also now common place to employ wide area high power or local area low power portable RF jamming equipment to deny the use of RF equipment by opposing forces. The RF jammers protect soldiers within different areas of a protective bubble from the RF detonation of road side bombs or IED's, however it also eliminates the use of low power RF communications such as Bluetooth™, Zigbee™ or WiFi etc. Jammers work in all types of environments. Threats from RF IED attacks are not just limited to desert warfare, but may also occur in shopping malls, office buildings, airports, bus stations, and other urban targets.
The modern soldier has a wealth of radio equipment that is critical for inter and intra squad communication as well as between the squad and forward operating bases and rear command centers. This entire radio network is used for voice, data, still video image and streaming video data image transmission in both directions as either information being communicated out of the battle zone or command and control information being directed into the battle area. Collectively this capability is known as C4I or command, control, communications, computers, and (military) intelligence and also as C4ISR command, control, communications, computers, intelligence, surveillance, and reconnaissance.
A method of, and apparatus for, providing a data communications capability on a soldier system in a RF denied area that is wireless, and which is not susceptible to radio frequency jamming, and cannot be intercepted at distance employs the transmission of data magnetically through inductive coupling. It is proposed herein that both power and data be transmitted inductively on the soldier. Not only would this allow the transfer of power and data without wires, tethers or umbilicals to the various devices of the soldier, but more importantly it would allow the local transmission of data on the soldier that cannot then be intercepted or in an area that has been denied RF communication either because of enemy, allied or self generated RF jamming.
I hereby incorporate by reference my U.S. patent application Ser. No. 11/922,788 (Publication No. 20090218884) entitled “Contactless Battery Charging Apparel”. The application describes sequential power transmission between a central power source carried on a soldier or person that is distributed through a wiring harness or conductive fabric worn on the soldier to inductive nodes located at various locations on torso of the soldier. The inductive power transfer nodes allow the transfer of power to rechargeable batteries in electronic devices distributed on the soldier without having physical contact or wires between the soldier and the components. The inductively coupled primary and secondary coils allow the transfer of power based on air core transformer theory.
Open platform inductive Near Field Communications (NFC) architecture is known. Prior art related to on-body inductive or near field communication however focuses on two applications. Both the patent to Palermo (U.S. Pat. No. 7,254,366 B2) entitled “Inductive Communication System and Method” and the patent to Lair (U.S. Pat. No. 7,149,552 B2) entitled “Wireless Headset for Communications Device” employ inductive near field communications to provide inductive coupling between hand held radios and a microphone/speaker or headsets.
A patent application by Devaul (US Patent Application Publication No. 2006/0224048 A1) entitled “Wearable Personal Area Data Network” describes the application of NFC to allow the communication between a master node or hub and remote node physiological sensors mounted on the body. The data communicated wirelessly from the sensors is analysed by the master node to determine the health status or mobility of the wearer. One application of the technology identified is placement of the system on a soldier to allow remote interrogation of a soldier on the battlefield to determine his health status and allow for earlier combat casualty care if so indicated. A patent application by Dinn (US Patent Application 2008/0227390 A1) entitled “Method and System for Relaying Signals from a Magneto-Inductive System Through a Voice Band System”, describes a man-portable station that can communicate through earth or rock using magneto-inductive transfer. The system enables secure low baud rate data and voice communications for users separated by line of sight obstacles located underground, underwater, or in dense urban environments. Vehicle-mounted systems are capable of providing secure communications over longer ranges. The operating frequency is between 300 Hz to 3 kHz and requires an antenna of at least 3 m in diameter laid on the ground. The device is commercially available under the Trade Mark “Rock Phone”. None of the prior art envision the application of NFC to provide wireless communication within a soldier system as described within this patent application.
When data is to be transferred from one electronic device to another or between a source and a receiver, there are four basic coupling methods that can be used. The basic arrangement of source, coupling path and receiver is shown in FIG. 1, where source and receiver are electronic hardware devices.
The four basic coupling mechanisms are: conductive, radiative, capacitive, and magnetic or inductive. Any coupling path may be broken down into one or more of these coupling mechanisms working together. Conductive coupling occurs when the coupling path between the source or transmitter 20 and receiver 22 is formed by direct contact with a conductor 21, for example a wire, cable, electronic textile (power and data backplane), or PCB trace. Radiative coupling or electromagnetic coupling occurs when the source or transmitter 23 and receiver 25 are separated by a large distance, typically more than a wavelength. The source radiates via an antenna an electromagnetic wave 24 which propagates across an open space and is picked up by the receiver. Radiative coupling is used by radios, wireless modems, Bluetooth™, Zigbee™ enabled devices etc. Inductive coupling occurs where the source or transmitter 29 and receiver 31 are separated by a short distance, that is within the near field of the transmission frequency. Inductive coupling can be of two kinds, electrical induction and magnetic induction. It is common to refer to electrical induction as capacitive coupling, and to magnetic induction as inductive coupling. Capacitive coupling between a transmitter 26 and receiver 28 occurs when a varying electrical field exists between two adjacent conductors 27 typically located within the near field, inducing a change in voltage across the gap. Inductive coupling or magnetic coupling occurs when a varying magnetic field 30 exists between two adjacent conductors usually coils, located within the near field, inducing a change in voltage in the receiving conductor or coil.
Inductive or magnetic coupling has been used in Radio Frequency Identification Devices (RFID's). At the basic level in an RFID an interrogator or primary circuit generates an alternating magnetic field that inductively couples with a transponder. The transponder or secondary circuit can be passive whereby it derives electrical energy from the magnetic coupling allowing it to transmit simple modulated data streams or it can be an active transponder. An active transponder has its own battery power source allowing it to both transmit back inductively to the interrogator a larger modulated data stream over a greater distance. There are two basic frequency ranges used by inductively coupled RFID devices, low frequency principally operates between 100-500 khz, and high frequency operates at a center frequency of 13.56 Mhz.